Tactile Wayfinding in Transportation Settings for Travelers Who Are Blind or Visually Impaired (2024)

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Final Report February 2024 Appendix A: Research Roadmap Page 78 A P P E N D I X A Research Roadmap (prepared in January 2020 as part of a project Interim Report for TCRP) Introduction This memorandum is the deliverable for Task 1 of TCRP Project B-46 providing a research roadmap based on conducting a comprehensive review of completed and ongoing research, standards, and current practices with respect to Tactile Walking Surface Indicators (TWSIs). TWSIs is an internationally recognized generic term that includes any tactile walking surface that is being intentionally used to provide warning or guidance to people with vision disabilities. Much of the review of international and United States (US) research and standards regarding TWSIs were compiled for a concurrent project for the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR), on which members of the TCRP B-46 team also worked, and which had an aim to provide research-based guidance for a TWSI to aid pedestrians with vision impairments in locating crosswalks and aligning to cross. A synthesis of US and international research, standards and guidance, and practice prepared under the NIDILRR project was provided to the panel for further understanding of what was learned under that project. The research team supplemented the NIDILRR synthesis with additional literature gathered on research supporting the need for visual contrast of TWSIs, the effect of snow on travelers’ abilities to detect TWSIs, the use of TWSIs as a delineator between the pedestrian area and the bicyclist area along a sidewalk-level separated bike lane (SBL), and the effect of TWSIs on people with mobility impairments. Additional findings shared from other related ongoing research projects as well as a summary of the state of practice of TWSIs being used in the US, which was gathered by reaching out and interviewing agencies identified as having installed TWSIs, also fed into the research roadmap. The research roadmap lays out what is known based on published research and preliminary findings from parallel projects and what is not known with regards to the use and effectiveness of TWSIs in order to clarify the scope and objectives for the Phase 2 and Phase 3 work plans by clearly distinguishing which research gaps are currently being addressed by other parallel or coordinated research projects and which shortfalls will be addressed through TCRP B-46. What is Known about TWSIs TWSIs have been used internationally since the 1960s, but there were no specifications to standardize their use in the US or elsewhere until the 1980s. Even now, little research has been conducted to demonstrate how different geometric patterns, which may be detectable by people who are blind or who have impaired vision, may also be discriminable from one another to inform how different TWSIs may be used together as a guidance system. This section explores what is known about TWSIs from the evidence-based research available.

Final Report February 2024 Appendix A: Research Roadmap Page 79 Detectability of TWSIs Tactile surfaces by and large fit into two categories: (1) attention fields which tend to use raised domes or cones or truncated domes or cones (TD), and (2) guidance surfaces (GS) which indicate a direction or path of travel to follow along which, internationally, is commonly strip of raised bars. In the international context, TDs may warn of danger, such as at a street crossing, a transit platform, or stairs; may indicate turns or intersections in tactile guidance paths; or may indicate points of interest such the locations of fare machines, kiosks, or tactile maps. “Detectable warning surface” (DWS) is a specific term used in the US to mean TDs as specified by the 2010 ADA Standards for Accessible Design (US Department of Justice 2010). DWS are required by the 2010 ADA Standards only at transit platform edges; however, the ADA Standards for Transportation Facilities (US Department of Transportation 2006) also require DWS at curb ramps. Proposed PROWAG (United States Access Board 2011) requires DWS at curb ramps, blended transitions, pedestrian refuge islands, and pedestrian at-grade crossings, as well as at boarding platforms and boarding and alighting areas at sidewalk or street level. DWS function like a stop line, indicating to pedestrians that there is a hazard directly ahead. In general, the tolerance for detectability is based on the spacing between the raised elements of a TWSI compared to the top width of the raised element, the height of the raised element, and the overall area of coverage of the TWSI. Raised elements spaced closer together are less detectable than those farther apart, but even detectable surfaces may be missed by people with low or no vision when approaching a TWSI perpendicular to its length if the width of the TWSI (i.e. the dimension in the approaching direction of travel) is such that people inadvertently step over it. Width of TWSI surface in direction of travel Research has been consistent in calling out the need for a TWSI to measure approximately 600 mm (24 in.) wide in the direction of travel across the surface in order to be detected. This is due to the natural gait and stride length of pedestrians. Surfaces shorter than that may be more likely to be stepped over and missed when approached perpendicularly or at an obtuse angle by people who are blind. In contrast, participants who were blind stopped approximately 90 percent of the time without stepping beyond DWS when the surface was about 24 in. deep in the direction of travel across it (Bentzen and Myers 1997; Hughes 1995; Mitchell 1988; O’Leary, Lockwood, and Taylor 1996; Peck and Bentzen 1987; Tijerina, Jackson, and Tornow 1994; Fujinami et al. 2005). The 24-in. width for DWS when placed along a transit platform edge was also found to reduce falls over the edge by delineating it in a detectable way not only for travelers with visual impairments but for all transit users (McGean 1991). Recent research in San Francisco by Bentzen et al., suggests that where it is not critical that pedestrians who are vision disabled actually come to a stop without stepping beyond TWSIs, such as crossing a GS path, a smaller width may still enable good detection (Bentzen, Scott, and Myers 2020). Geometry of TWSIs for Detection Proportions between three key dimensions determine whether a TWSI will be detected provided the surface is sufficiently wide that it is not stepped over: height of the raised element, top width or diameter of the raised element, and spacing between raised elements. More research has focused on the center-to- center spacing between raised elements in relation to the top width of the raised element needed for detectability. From this research, we know that top widths or diameters between 18-35 mm and the center- to-center spacing between 60-70 mm (domes) and 75-86 mm (bars) are detectable (National Institute for Technology and Evaluation 1998; Sawai, Takato, and Tauchi 1998). In each of these studies, height of the raised element was around 5 mm. The specifications for DWS in the 1991 ADA Standards were found to be detectable (Bentzen et al. 1994).

Final Report February 2024 Appendix A: Research Roadmap Page 80 Internationally and in the US, the height of TWSIs used in practice, and in fact required by most standards, is around 5mm. This height has shown to be detectable and discriminable by people with vision disabilities (NITE, 1998; 2000; Sawai et al., 1998; Bentzen et al. 1994) while not impeding people with mobility impairments. In fact, the height of the raised surface is particularly important when TWSIs are used in outdoor areas where the surrounding pavement is likely to be less uniformly smooth. Gap spacing between the edges of the tops of raised elements has not been mentioned in previous reports; emphasis has been on the center-to-center spacing between the raised elements. DWS, which have the broad range of gap spacing in relation to raised surface widths permitted by the 2010 ADA Standards (center-to- center spacing of 41 to 61 mm, base diameter of 23 mm to 36 mm, and top diameter of 50 to 65 percent of the base), have not all been tested and demonstrated to be reliably detectable. TDs having center spacing of the domes as close as 42.9 mm were not highly detectable and discriminable according to the research (National Institute for Technology and Evaluation 1998; National Institute for Technology and Evaluation 2000; Sawai, Takato, and Tauchi 1998). One surface pattern – a sinusoidal geometry intended for navigating along a path - was initially preferred by cane users over raised bar patterns given they reported the cane was less likely to “stick;” however four separate studies found this pattern to be minimally detectable under foot (Behling 2008; Böhringer 2003; Böhringer 2007; Ståhl, Almen, and Wemme 2004). Indented, grooved geometric designs also were not sufficiently detectable by people with vision impairments (Bentzen, Barlow, and Tabor 2000). The United Kingdom is a source for extensive testing of geometry of detectable surfaces. Researchers investigated seven distinct surface patterns and found them to be detectable and discriminable (Gallon et al, 1991; Gallon, 1992; Gallon and Fowkes, 1992; Gallon et al., 1992; Savill et al., 1998). These seven different surface patterns, each of which conveys a different meaning and are to be installed at different locations, were compiled into national guidance based on that research, which also confirmed that people with visual impairments could remember the meaning of each surface once taught (Guidance on the use of Tactile Paving Surfaces 1998). More recent personal communication with the director of Access Design Solutions UK Ltd. suggests that most people are identifying the surface types more by the context of the environment in which they are located rather than discriminating differences in surface geometries (Bentzen 2018). Use of TWSI as a delineator along sidewalk-level SBLs Many European countries have installed extensive networks of separated bicycle lanes (SBLs), but they are an emerging facility design in the United States. The treatment is becoming ever popular due to the safety benefits it affords bicyclists given the physical vertical and horizontal separation from motor vehicle lanes. One variation of this design includes sidewalk-level SBLs, where curbing with or without a buffer zone separates the bicycle lane from the motor vehicle lane such that the bicycle lane is flush with the pedestrian zone. SBLs are unique from shared use paths in that shared use paths are facilities meant to be shared by pedestrians and bicyclists, while SBLs are designated only for bicyclists (and potentially users of other emerging vehicles under the micromobility frame.) Accessibility advocates are rightfully concerned about the possibility that people who are blind will not know when they may encroach the bicycle lane without some detectable indicator to warn, delineate, or otherwise differentiate the boundary between the pedestrian space and the bicyclist space. There is an additional need to ensure that whatever indicator is used is not a crash risk to bicyclists nor an impediment to people with mobility impairments. While an obvious answer may be to use DWS, as is standard along transit platforms, cost and space concerns due to the length of a TWSI needed (and at 24 in wide) for this type of application may be daunting, and, in practice, DWS may also carry meaning as marking a designated location to cross where there is no curb (Elliot et al. 2017). Therefore, there is some concern that delineating the length of an SBL with DWS may confuse people as to where crossing locations are located. Further, DWS currently have a very discrete meaning in US standards and guidance; they are to be used only in narrow applications to define the boundary between pedestrian and vehicular ways such as roadways and transit platforms. While

Final Report February 2024 Appendix A: Research Roadmap Page 81 DWS in the US are not intended to serve as a GS, one study from Japan found that 84% of the visually impaired people interviewed used the DWS at railway platforms to follow along as a guide, which suggests that, in practice, certain applications of the domed pattern may already serve two purposes – to warn and to guide (Mizukami et al. 2002). A delineator for a sidewalk level SBL should serve not only to warn and guide pedestrians who are vision disabled (should they choose to follow it), but also to deter bicycle intrusion into the pedestrian path of travel. A distinct and highly identifiable TWSI may therefore be appropriate as a delineator for sidewalk level SBLs. In the US, the use of DWS to provide guidance or to define the limit of the pedestrian access route in shared spaces is also not recommended (Elliot et al. 2017). Little research has been published to-date to determine how and what type of TWSI could serve as a sidewalk-level SBL delineator, but much of what is known is based on studies conducted in the United Kingdom (UK). Williams identified a raised trapezoidal surface that was detectable and usable by pedestrians with vision disabilities as a delineator between bicycle and pedestrian sides of a sidewalk level separated bike lane, and this TWSI subsequently became recommended practice in the UK’s guidance (Williams 1987; Guidance on the use of Tactile Paving Surfaces 1998). Prior to the guide, additional research by Savill et al. tested 10 different TWSIs with a raised surface width of 150 mm as SBL delineators: five trapezoid patterns at different heights (12 mm or 20 mm) and of different material, and five other raised patterns using variations of bars laid out like rumble strips; bars in a U shape laid out longitudinal to the bicycle lane; single, large, continuous longitudinal bars with a rough texture; continuous inverted-T shaped bars; and a continuous domed strip. Of the 48 participants with visual impairments, more preferred the trapezoidal surface made of concrete or a bitumen-based compound than any other TWSI delineator, and all were able to locate it. Interestingly, these two 20mm high trapezoidal strips preferred by participants with vision disabilities were judged to be least safe by the participant cyclists, who also found the 20 mm raised element to be too high in all cases (Savill, Gallon, and McHardy 1997). It is worth noting that surfaces higher than 6.4 mm (or 13 mm with beveled edges) would not comply with the 2010 ADA Standards and could be a tripping hazard or impediment to people with mobility impairments. Childs et al. conducted similar research in 2010, testing 15 delineator types at different surface widths, geometries, and orientations with respect to the direction of pedestrian travel. The 800 mm wide TD, GS and corduroy geometries were all detected more than 96 percent of the time, but the GS and corduroy surfaces were rated as more difficult to detect than the TD surface. Additionally, both GS and corduroy surfaces were more difficult to detect when oriented perpendicular to the direction of travel. All three performed well for traversability tests with people with mobility impairments. In contrast, the trapezoidal geometry did not perform as well for detection by those with visual impairments (but it was only 150 mm wide) nor for crossing by those with mobility impairments (and it was 20 mm high) (Childs et al. 2010). Safety and negotiability for people with mobility impairments It is important to recognize the need to compromise between maximizing detectability for people with visual impairments while not decreasing safety nor increasing discomfort for people with mobility impairments. Peck and Bentzen found no issue with DWS at transit platforms (1987), and several independent studies found minimal effects observed or reported for different DWS patterns or raised bar patterns with maximum heights of 5.08 mm when measuring effort, slippage, stability, and wheel or tip entrapment even when placed on ramps with a 1:12 slope (Bentzen et al. 1994; Hauger et al. 1996; Hughes 1995; Peck and Bentzen 1987). Bentzen et al., in ongoing research sponsored by NIDILRR, found that raised bar GS traversed with the bars parallel with the direction of travel were more negotiable and more preferred by people with various mobility disabilities, using a variety of aids, than similar bars perpendicular with the direction of travel, although both were crossable (Bentzen, Scott, and Myers 2020). Bentzen et al. in research for the Better Market Street project in San Francisco, found that neither DWS, GS of two different geometries, nor a raised trapezoid were a barrier to crossing by people having mobility disabilities, although the raised trapezoid was not preferred by people with mobility disabilities for use as a delineator at SBLs at sidewalk level (Bentzen, Scott, and Myers 2020).

Final Report February 2024 Appendix A: Research Roadmap Page 82 Comments gathered through the development of ISO 23599 suggest that the relationship between gap spacing between raised elements and the top width of the raised element may also impact safety or comfort of people with mobility impairments when traversing TWSIs, as it was noted that wider raised bars (presumably with narrower gaps) were less adverse given less vibration for wheeled mobility aids (“ISO 23599:2012 Assistive products for blind and vision-impaired persons – Tactile walking surface indicators” 2018). Research reported in 2006 tested seven different TWSI surfaces to delineate pedestrian paths through shared space environments from both the vision-impaired and mobility-impaired perspectives, but the results are also applicable when considering how to distinguish an SBL that is flush with the sidewalk. Both the 150 mm wide, 20 mm high trapezoidal strip and a 400 mm wide, 5 mm high GS strip consisting of five raised bars spaced 45 mm apart performed well with participants with vision impairments. While 53 percent of those participants with mobility impairments indicated the trapezoidal or GS indicators to be acceptable, 87 percent rated the former and 60 percent rated the latter as easy to cross. Ultimately, the GS was concluded as acceptable for indicating a path to follow but not to delineate a boundary while the trapezoidal indicator was found to be effective for both (Testing proposed delineators to demarcate pedestrian paths in a shared space environment: Report of design trials conducted at University College London Pedestrian Accessibility and Movement Environment Laboratory (PAMELA) 2008). Need for visual contrast for people with low vision While TWSIs are primarily intended to be detected based on tactile information conveyed through the geometry of their surface patterns, most people who are legally blind are not fully blind. It is therefore the consensus in US and international standards and guidance that TWSIs should have high visual contrast with surrounding surfaces. In early research on visual contrast for DWS (Templer, Wineman, and Zimring 1982; Bentzen et al. 1994; O’Leary, Lockwood, and Taylor 1996; Bentzen and Myers 1997; Kemp 2003), yellow DWS (particularly federal yellow--13591), also known as safety yellow) were, overall, found to be highly visually detectable based on performance. Predictably, higher contrasts between the warning surface and the adjacent surface were found to be more detectable by participants than lower contrasts. However, these studies varied widely in the number of participants, the types and number of detectable warning materials and contrasts tested, procedures used, and the amount of detail provided in the reports. Participants in these studies generally were recruited based on self-reported visual ability. Three of the studies used six or fewer participants and are informal assessments of particular products rather than scientifically rigorous experiments. Jenness and Singer conducted a highly controlled study to support the development of a detailed standard for the US regarding the color and contrast for DWS to aid in visual detection. They tested 13 different colors or color patterns ranging in reflectance from 0.2 to 0.82 on four different colored sidewalks (representing new concrete, older and darker concrete, asphalt, and red brick) for conspicuity and luminance contrast under daylight conditions to determine how visual detection of DWS was affected. While the 50 participants reported that they could not reliably visually detect the boundary between sidewalks and streets without the DWS, more than 90% of participants could see it when standing eight feet away when it had a luminance contrast of at least 60% (Jenness and Singer 2006). Indeed, the luminance contrast between the DWS and the simulated sidewalk was a strong predictor of detection and conspicuity rating of the DWS; however, even with high luminance contrast, dark DWS on a dark sidewalk were detected less often than would have been predicted based on luminance contrast alone. Color, such as reds and yellows, were more detectable and conspicuous than white, black, or grey. Reflectance also predicted detection and conspicuity; lighter colors were better than darker colors, and DWS similar in color to the adjacent surface were seldom detected. Based on the results of this research, Jenness and Singer (2006) recommended that the choice of color for DWS be determined by luminance contrast with the adjoining surface, light on dark or dark on light, and that combinations should not be used in which the reflectance of the lighter color was less than 10 percent. They recommended that any standard express both a minimum luminance contrast and a minimum

Final Report February 2024 Appendix A: Research Roadmap Page 83 reflectance value for the lighter of the two surfaces. Federal yellow was recommended where the desire was to have a single, uniform color for DWS because of its high conspicuity rating across different levels of luminance contrast. Yellow is especially effective in association with dark sidewalks. Where sidewalks are light, a good choice for both detection and conspicuity is a dark brick-red (red-orange). Several Japanese studies also support the need for not only color contrast between the installation surface and TWSIs, but also improved ambient lighting to increase luminance contrast, and found that yellow had the highest detection rate at low light levels (Seiji Mitani et al. 2007; Seiji Mitani et al. 2009; Seiji Mitani et al. 2011). Maintenance of TWSIs for detectability Poorly maintained or badly installed TWSIs can lead to confusion or possibly harm to those who rely on them. Poor continuity, broken or missing tiles, incorrect installation, or obstacles in the path of the TWSI can render the installations ineffective at providing wayfinding (Pembuain, Priyanto, and Suparma 2019). When studying different materials in relation to detectability for trapezoidal GS, Savill et al. noted that the thermoplastic type that was being used at the time tended to slump and lose its height profile (Savill, Gallon, and McHardy 1997). Other practical evaluations of durability and maintenance concerns have been conducted on DWS products. Several studies were undertaken by state departments of transportation in the early 2000’s, though most originate from states where freezing and snow conditions are common. An FHWA report out of Oregon, a less extreme climate, examined environmental impacts on a set of DWS tiles over time, and, of the products tested, the durability of the visual contrast was the cause of the most concern (Kirk 2004). Long term durability issues center around general degradation of the material, including fading and reductions in the color and color contrast (Estakhri and Smith 2005). A recent study which evaluated certain polymeric DWS products noted the effects of sunlight on the materials, especially with regards to color fading (Na et al. 2018). The report titled Synthesis of Maintenance and Durability Information for Detectable Warnings on Sidewalks (NCHRP 20-07/Task 177), completed in 2005, is a collection of research and relevant information regarding maintenance of DWS (Estakhri and Smith 2005). The report includes a list of types of materials available, and an examination of pertinent construction and installation, maintenance, and durability topics. Snow and ice are the central maintenance considerations. Landry et al found that detectability of DWS was no different when they were covered with a light layer of snow; however, Couturier and Ratelle found that GS were difficult to follow when snow-covered (Landry, Ratelle, and Overbury 2010; Couturier and Ratelle 2010). They also looked at whether the color of the TWSI surface impacted the rate of snow melt, thus potentially increasing detectability, and found that it does not melt any more readily on darker colored surfaces. Where frequent snow removal is required, materials like cast iron or solid steel work better based on field tests of different materials (Landry, Ratelle, and Overbury 2010; Couturier and Ratelle 2010). AASHTO’s National Transportation Product Evaluation Program (NTPEP) established a standard testing protocol for evaluating the long-term durability of DWS. Products are submitted voluntarily by manufacturers. The testing agency reports the results via the Datamine portal, and agencies set local criteria for whether the products are acceptable for their specific needs (AASHTO National Transportation Product Evaluation Program 2019). In general, knowledge and experience that US practitioners have acquired from installing and maintaining DWS should apply to any TWSI produced with similar material and applied and maintained in similar ways. (Bentzen, Barlow, and Tabor 2000; Ketola and Chia 1994).

Final Report February 2024 Appendix A: Research Roadmap Page 84 Using TWSIs to identify crossing locations and establish a heading to cross TWSIs have an opportunity to not only to call attention to a location (e.g. TD) or provide a path to follow along (e.g. GS) but to better orient a person with low or no vision in a specific direction of travel. DWS may indicate a crossing location, but they are not intended to be used by people who are blind to establish a heading to cross that lines up with the direction of travel to be taken when crossing the street. In the US, they are not positioned to indicate crossing direction, but only the boundary between the pedestrian and vehicular space. DWS do not promote accurate direction-taking (A. Scott 2012). Further, for people walking along a sidewalk, DWS do not help those with vision impairments to locate a crossing point, particularly at midblock crosswalks, where they may be difficult to find. As such, and given the variability in reliability of other cues by other objects that may or may not be present to orient people to cross (e.g. poorly placed or oriented curb ramps, poor placed or oriented accessible pedestrian signals, etc.), it can be beneficial to determine a TWSI or arrangement of TWSIs used in combination that can aid with these two crossing tasks: identifying crossing locations and establishing a heading that aligns with the intended direction of travel through the crosswalk. Research to-date has proven mixed results in testing TWSIs as a system for these uses. Two studies were found that investigated the use of TWSIs to aid in the first task – finding the crossing location. Langevin et al. found that people with vision impairments could successfully detect a GS installed the full width of the sidewalk and follow the raised bars oriented in the direction of the crosswalk to the TD at its terminus, thereby successfully locating the crossing, but raised bars in this orientation did not aid in establishing a correct heading (Langevin et al. 2013). However, Bentzen et al., in research at roundabout and mid-block crossings, found that installing GS the width of the sidewalk with bars oriented perpendicular to the direction of travel on the associated crosswalk not only resulted in almost perfect accuracy in finding the crosswalk, but increased accuracy in establishing a correct heading from approximately 50% to approximately 75% (Bentzen et al. 2017). This research was the motivation for the NIDILRR project on this subject, the results of which will be available in 2020. Bentzen et al. were motivated to orient the raised bars perpendicular to the direction of travel across the crosswalk by five studies that investigated the use of raised bars oriented perpendicular to the intended direction of travel and found that participants with vision impairments could better align to cross, than when aligning with raised bars parallel to the direction of travel (A. Scott et al. 2011; A. C. Scott et al. 2011; Takeda et al. 2006; Bentzen et al. 2017). Discriminability of TWSI patterns from one another When TWSIs are used together as a system, they must be highly discriminable and identifiable because each type calls for a different response from the vision disabled traveler. The seminal research testing discriminability of TWSI patterns from one another comes out of Japan and is founded in studies conducted in primarily by Japan’s National Institute of Technology and Evaluation (NITE), which tested 81 combinations of nine TD and nine raised-bar GS of different geometries (National Institute for Technology and Evaluation 1998). This was the only research found that systematically varied the dimensions of raised bar and TD elements as well as the spacing between the raised elements to identify optimal geometries for each surface type such that each pattern type is not only detectable but also identifiable from one another under foot. NITE and Sawai et al. found that GS, where the top width of raised bars is between 18 mm to 35 mm and the center-to-center spacing between bars is between 75 to 86 mm, are detectable and discriminable. Indeed, this research found that GS with center spacing 50 mm or less is significantly less detectable and discriminable. Similarly, TDs with center spacing as close as 42.9 mm were not highly detectable and discriminable (National Institute for Technology and Evaluation 1998; National Institute for Technology and Evaluation 2000; Sawai, Takato, and Tauchi 1998). Subsequent research confirmed that the Japanese standard for the GS pattern (top width of 17 mm and center-to-center spacing of 75 mm) and

Final Report February 2024 Appendix A: Research Roadmap Page 85 TD patterns (base diameter of 22 mm, top diameter of 12 mm, and center-to center spacing of 55 mm to 60 mm) were also detectable and discriminable by those using a long cane (S Mitani et al. 2007). Height also plays a role in discriminating GS from TDs. Japanese research concluded that TWSIs must be 4-5 mm in height for good detectability and discriminability (National Institute for Technology and Evaluation 1998; National Institute for Technology and Evaluation 2000; Sawai, Takato, and Tauchi 1998). DWS are required to be 5 mm high, based on research by Bentzen et al., which also found that when DWS are installed in association with a rough surface, they are less detectable than when installed on smoother surfaces (Bentzen et al. 1994). This is well accepted internationally (ISO 23599), although emerging research suggests that the height required for good detectability and discriminability when installed in association with smooth surfaced might be somewhat less (Nakamura et al. 2011). The only study found outside of Japan to determine discriminability of different TWSIs was conducted by Stahl et. al in Sweden. They tested the sinusoidal surface and found it was not highly discriminable from TDs (Ståhl, Almen, and Wemme 2004). Using different TWSI patterns as a system Research found to demonstrate how arrangements of TDs, GS, or other TWSI patterns may work together as a wayfinding system to aid in navigation from point A to point B comes from Canada. Canadian research in 2010 focused specifically on testing GSs paths combined with TDs to determine if marking intersections of paths was useful for identifying where to make a turn in a route. They compared participants’ abilities to navigate turns in GS paths configured into T-intersections, where the choice point of intersection was either indicated with an area of TDs larger than the path width or not. Landry et al. found no effect in using the TDs as a choice point indicator (Landry, Ratelle, and Overbury 2010). This is a surprising result and may suggest that common practices observed internationally to mark path turns and intersections are not necessary. Standards and the State of Practice of TWSIs This section summarizes the similarities in standards specified for GS and TDs around the world and notes unique patterns, practices, or locations where TWSIs may be used differently in a given country. Since the US does not currently have a standard for a GS, there is minimal usage of this surface type upon which to draw firm conclusions about the state of practice across the country. That said, proactive local agencies with strong accessibility advocates in their communities are seeing the need to provide some type of guidance path and are trying different indicators in different settings while largely drawing upon international standards, guidance, and practices. Table 1-1 and Table 1-2 shows the International Organization of Standards (ISO), Americans with Disabilities Act Accessibility Guidelines (ADAAG), Japan Industrial Standard (JIS), Canadian Standards Association (CSA), Australian/New Zealand Standards (AS/NZS), and Deutsches Institut für Normung (DIN) German standard ranges and the UK guidance for spacing of elements based on the size of the raised element for both TDs and raised bar GS. More details on standards and practices outside of the US are provided in the Bentzen et al. report for NIDILLR (2021) while more details on practices for GS specifically are provided in Appendix B.

Final Report February 2024 Appendix A: Research Roadmap Page 86 Table A-3. Comparison of standard dimensions for TDs across different countries. Standard Top diameter of truncated domes/cones (mm) Center-point spacing of domes/cones (mm) Gap between dome top edges† (mm) Depth or Width of TD Surface (mm) ISO 23599 12 42 to 61 30 to 50 560 JIS T 9251 12 55 to 60 43 to 48 none given ISO 23599 15 45 to 63 30 to 48 560 ADAAG 2010 11.5 to 23.4‡ 41 to 61 17.6 to 49.5 610 ISO 23599 18 48 to 65 30 to 47 560 ISO 23599 20 50 to 68 30 to 48 560 ISO 23599 25 55 to 70 30 to 45 560 CSA B651-18 Same as ISO range Same as ISO range Same as ISO range 600 to 650 AS/NZS 1428.4.1 25 50 25 600 to 800 Note: †Gap spacing dimensions are not specified in Standards but were computed based on other standard dimensions. ‡Top diameter range is computed as 50 to 65 percent of the base diameter, which can range from 23 to 36 mm. Table A-4. Comparison of standard dimensions for GS across different countries. Standard Top width of flat-topped bars (mm) Center-point Spacing of raised bars (mm) Gap between bar top edges† (mm) Depth or Width of GS where it is primarily to be followed (mm) ISO 23599 17 57 to 78 40 to 61 250* JIS T 9251 17 75 58 None given ISO 23599 20 60 to 80 40 to 60 250* ADAAG 2010 -- -- -- ISO 23599 25 65 to 83 40 to 58 250* ISO 23599 30 70 to 85 40 to 55 250* CSA B651-18 Same as ISO range Same as ISO range Same as ISO range 250 to 300 ‡ AS/NZS 1428.4.1 25 75 50 300 Note: †Gap spacing dimensions are not specified in Standards but were computed based on other standard dimensions. *Effective width, i.e. the distance between the outermost edges of the outermost raised elements. Where the GS must be detected from an angle of approach, the effective width must be 550 mm (ISO 23599). ‡Base surface width. Where the GS is installed across a path of travel to indicate a facility or diverging route, the width must be 600 to 650 mm (CSA B651-18).

Final Report February 2024 Appendix A: Research Roadmap Page 87 Outside the US Standards In 2008, the European Committee for Standardization produced the first international standard on dimensions for TWSIs including six types of raised bar surfaces, two dome surfaces, two grooved surfaces, and one each of pyramid, cylinder, lozenge, and trapezoidal surfaces. The dimensions for each of these raised elements varied widely (CEN/TS 15209:2008 Tactile Paving Surface Indicators Produced from Concrete, Clay and Stone 2008). By 2012, all countries who were part of the development of the ISO 23599 standard were already using some type of dome arrangement as a warning surface indicator, and, where guidance paths were being installed, most countries used raised bars. Everywhere except in the US, countries were using domes together with raised bars as a TWSI system, where the domes served as attention fields not only for warning of hazards but also to indicate turns, intersecting paths, and key points of interest like bus stops, elevators, tactile maps, or other waypoints (Bentzen 2019). ISO 23599 considers the relationship of the spacing between raised elements to the size of the raised element with the understanding that smaller elements can be closer together and still be detectable while larger elements need more gap spacing between to maintain detectability. The ranges in patterns and dimensions are based on the research known about detectability and discriminability. All raised elements can be between 4 to 5 mm in height, which is also supported by research as being high enough to detect without being too high as to be an impediment to people with mobility impairments. Because TDs can have different meanings internationally, depending on if they are indicating a hazard or simply calling attention to a certain location, ISO 23599 provides specifications on how big each type of surface are should be: attention fields (i.e. TDs) must be at least 560 mm wide and deep (in direction of travel). Where used to indicate a hazard, TDs must extend the full width of the hazard and are recommended to be set back 300 mm from the hazard. GS surfaces must be at least 550 mm wide, and a clear path of 600 mm must be provided on both sides of the GS path for travel. Canada’s accessibility standard is more prescribed in the many different locations where TDs are to be used. It specifies their installation at curb ramps, curb cuts of medians and pedestrian refuge islands, tops of stairs, reflecting pools, and transit platforms to extend the full length of the hazard they demarcate. They are also used at turns and decision points along GS paths. TDs are also used along pedestrian routes where no other vertical separation like curbs, railings or barriers separate them from the vehicular way. GS surfaces must be installed in large open floor areas like transit terminals to lead from the entrance to major destinations. Like ISO 23599, Canada dictates that the GS path must have clear space of at least 600 mm on each side (CAN/CSA B651-18 Accessible Design for the Built Environment 2018). Similarly, the Australian/New Zealand (AS/NZS) standard calls for TDs (or truncated cones) to delineate pedestrian space from vehicular space or other hazards like stairways, escalators, and moving walkways when used as warning fields. TDs are also used at turns or intersections of GS paths. Interestingly, the AS/NC standard does not require TDs on curb ramps where slope is 1:8.5 or greater, as it is assumed travelers with visual impairments will readily detect the street edge given the narrower angle between the street and ramp due to the steep slope. Color contrast or luminance of TWSIs are also specified in many countries’ standards. Within the US, the 2010 ADA Standards requires visual color for DWS, but simply describes this as “light-on-dark or dark- on-light.”. The UK also requires TDs to contrast with the adjacent pavement and specifies colors; red should be used at controlled crossings and buff (or another contrasting color that is not red) should be used at uncontrolled crossings. Canada also requires a difference in luminance for both TDs and GS; their standard recommends yellow for TDs but discourages the same color for GS applications. ISO 23599 requires a luminance contrast between all TWSIs and their surrounding surfaces of a minimum of 30% (using the Michelson contrast formula). However, where TWSIs are being used to warn of hazards, the minimum luminance contrast is required to be at least 50%. Likewise, where discrete truncated domes are installed rather than elements that are integrated into a single TWSI surface, the

Final Report February 2024 Appendix A: Research Roadmap Page 88 contrast must be at least 50%. In accordance with the recommendation of Jenness and Singer, ISO 23599 requires a 40% minimum reflectance value of the lighter surface. Recognizing that high visual contrast is not always possible, ISO 23599 requires the use of a continuous adjoining band of compliant contrast with a minimum width of 100mm around or beside a TWSI installation. ISO 23599 contains a discussion of various methods of measuring and calculating luminance contrast that are used in different countries (Jenness and Singer 2006). Interestingly, the two countries from where much research on TWSIs comes – Japan and the UK - do not officially have standards specifying how or where they are to be used in the public right of way. In fact, the UK has no standards for TWSIs, but its Guidance on the use of Tactile Paving Surfaces is generally followed as such. Given the wide variation in how and where TWSIs were already being used in participating countries of the ISO23599, guidance on how and where to use TSWIs consists of a number of representative figures showing installation schemes from various countries for various situations (Guidance on the use of Tactile Paving Surfaces 1998). Practices In Denmark, Sweden, and Germany, raised bars GS are only used on sidewalks where natural landscaping or other cues in the built environment are nonexistent or provide insufficient information to travelers with vision impairments. Other European and Asian countries are more liberal in GS path applications where they can be observed along sidewalks that may not necessarily need TWSIs elsewhere in order for pedestrians who are blind to follow along a route. There is wide variation in the use of TWSIs across Germany. The country’s DIN 32984 also provides recommended practice for both indoor and outdoor use of TWSIs. TDs mark turns and intersections in GS paths. They can also indicate crosswalk locations when placed across the width of the sidewalk and lead to raised bars oriented parallel to the direction of travel along the crosswalk to aid in aligning to cross though literature supporting this practice is lacking. Germany also uses raised bars as a hazard indicator when placed parallel to the curbline where there is no curb to indicate locations where pedestrians with vision impairments are not to cross (DIN 32984 Bodenindikatoren im offentlichen Verkehrsraum (Floor Indicators in Public Space) 2011). In both Australia and the UK, TDs are installed so that the back edge of the TD is perpendicular to the pedestrians’ path of travel through the crosswalk to aid with aligning to cross. Scott et al. investigated the accuracy of DWS (TD) alignment and found alignment to be significantly less accurate with DWSs than with raised bars oriented perpendicular to the intended direction of travel (A. Scott 2012). Inside the US Standards As previously mentioned, the 2010 ADA Standards and the ADA Standards for Transportation Facilities (2006) specify the dimensions for DWS and, taken together, require them at the edges of transit boarding platforms and at the bottom of curb ramps. They are not to be set back from platform edges and curb lines as is more common internationally. DWS surfaces must be 610 mm deep (in the direction of travel). Currently, there are no US standards for specifications for use of GS of any pattern. Existing or upcoming guidance While not standards, the US Department of Transportation (US DOT) published the Accessible Shared Streets guidance in 2017. The guide contains a section titled ‘Tactile Walking Surface Indicators and Detectable Edges’, which covers currently understood best practices for using TWSIs in shared street

Final Report February 2024 Appendix A: Research Roadmap Page 89 environments in the United States (Elliot et al. 2017). Two other nationally recognized organizations provide guidance on the use of TWSIs beyond TDs. The National Association of City Transportation Officials (NACTO)’s Urban Street Design Guide recommends tactile strips along entrances to shared use paths (National Association of City Transportation Officials 2013). The American Society of Landscape Architects (ASLA) recently released a Universal Design guide, which also contains recommendations for “perpendicular tactile paving” to indicate hazards to those with no or low vision (“Universal Design | asla.org” 2019). Two other publications under development are anticipated to provide additional guidance on the use of GS. The American Public Transit Association (APTA) is working on a Transit Universal Design Guidelines which emphasizes that tactile paths should be ‘distinct from detectable warning surfaces to preserve the communication of essential safety concerns’ (BART 2019). The next edition of the AASHTO Bicycle Facilities Guide currently under review is also recommending tactile indicators as separation between pedestrian and bicycle ways when they are on the same level (Schulthiess and Chrzan 2019). Practice Given the lack of standards or guidance for GS usage in the US, a few agencies recognize the need for and are exploring some type of tactile cue to aid people with low or no vision in navigating public spaces where there may not be other wayfinding cues in the built environment, such as landscaping, to follow along or identify key waypoints. Through existing professional networks, fourteen transit and municipal agencies were identified as having some form of TWSI for wayfinding. Each agency was contacted three times with a request for a short interview. A total of ten agencies were ultimately surveyed. Thirty-minute stakeholder interviews were conducted over the course of six weeks during the study period. Notes from the phone calls were compiled and sent to interviewees to review. Findings from these interviews are further synthesized in Appendix B. What is Not Known about TWSIs – Current Research Gaps There is considerable international usage of both attention pattern surfaces (e.g. truncated domes, DWS) and guidance pattern surfaces (e.g. raised bars). However, there is little research to demonstrate the detectability and discriminability of these different types of patterns from one another or from other TWSIs beyond the Japanese research. Surfaces to be used in combination must not only be detectable from approach surfaces such as concrete and various paving and flooring surfaces adjacent to the TWSIs, but they need to be discriminable from one another, and identifiable as to which indicator it is. It is important that users who are following a GS to a destination indicated by DWS, such as a street crossing or a transit platform, readily recognize when they arrive at the DWS. Based on the published research summarized previously, the following gaps are highlighted. Gap 1) What gap spacing between raised elements in relation to the top width of the raised elements is acceptable for discrimination of TWSIs? In general, it is recognized that detectability underfoot is served through a combination of height of the raised element, top width of that element, and spacing between the raised elements. While much research on detectability has focused on the center-to-center spacing between the elements, we have come to think that the gap spacing between the edges of the raised elements in relation to the top widths may be more crucial for discriminating different types of TWSIs from one another. Not all the geometries of DWS currently allowed in the 2010 ADA Standards have been verified as detectable through research, and there are concerns that those with narrower gap spacing may not be identifiable underfoot as DWS and may therefore be more difficult to discriminate from a GS path. Further, no US research on discriminability between DWS and GS has been conducted except the recently limited research by Bentzen et al. in San

Final Report February 2024 Appendix A: Research Roadmap Page 90 Francisco (Bentzen, Scott, and Myers 2020). Japanese research suggests that smaller raised elements more widely spaced are most detectable and discriminable (National Institute for Technology and Evaluation 1998; National Institute for Technology and Evaluation 2000; Sawai, Takato, and Tauchi 1998). Gap 2) Are choice point indicators needed, and if so where, and what surface type should be used? Research is also needed to determine whether there is a need for a special surface to indicate the intersection of GS or a turn along a GS. Internationally, it is common to use a larger square of TD surface (e.g. 550 to 650 mm square) at turns and intersections of GS with narrower widths (e.g. 250 to 300 mm wide). However, in the US, the use of TDs is limited to defining boundaries between pedestrian and vehicular ways. Further, the little research found on using a system of TWSIs in this manner suggests that these choice point indicators may not be necessary (Langevin et al. 2013). More research is needed to confirm or refute earlier research on the effectiveness of choice point indicators at turns and intersecting paths. If we learn that a special surface is needed, research will also be needed to determine what the surface should be and how it should be used. It will be important to then consider three unique geometric patterns – each discriminable from one another both underfoot and by cane – to convey warning locations (e.g. DWS via TDs), paths and routes (e.g. GS via raised bar or other pattern), and path turns or nodes (via some other TWSI). Gap 3) What TWSI is appropriate to delineate sidewalk-level separated bicycle lanes in the US? No published research was found that robustly tested different TWSIs’ impact on pedestrians with vision impairments, pedestrians with mobility impairments, and bicyclists to determine an optimal geometric design to mark the boundary between the pedestrian space and the bicyclist space that functioned suitably for all three types of travelers. Based on the research found, TDs, trapezoidal GS, corduroy GS, or raised bar GS may all serve the role to warn and/or mark the edge of the pedestrian zone while providing a path along which people with vision impairments could follow. But, depending on the orientation of the longitudinal raised elements of a GS, the width of the TWSI, and the top width to gap space ratio of the raised element the TWSI’s tested thus far are either more difficult to detect by those who are blind or more difficult to traverse by those with a mobility impairment or who are bicycling. This is concerning as several agencies in the US are using raised bar GS to delineate sidewalk-level SBLs which may not necessarily be the most appropriate geometry. FHWA’s guidelines on shared streets additionally caution the use of directional indicators, such as GS bars, for delineation or edging purposes, which could confuse their meaning (Elliot et al. 2017). Further, it is unclear how a person with impaired vision would be able to know which side of the TWSI to follow along and whether they are in the bicycle lane. Gap 4) Should there be different TWSI height specifications when used indoors vs. outside? Research is clear in supporting a height of around 5 mm as being detectable, and in fact, most TWSI standards require that specification. Some research suggests that shorter TWSIs may still be detectable, possibly even as short as 2.5 mm but the results are mixed as far as what minimum height threshold could be considered and likely depends on the smoothness of the adjacent surface. (Nakamura et al., 2008; Nakamura et al., 2009; Nakamura e al., 2011) This has implications when considering the use of TWSIs inside buildings such as transit stations or terminals, where the adjacent flooring may be more consistently smooth. In such circumstances, shorter TWSIs may be preferred to minimize impacts to people with

Final Report February 2024 Appendix A: Research Roadmap Page 91 mobility impairments. Indeed, German practice illustrates clear distinctions of height depending on if the TWSI application is indoors versus outdoors. Gap 5) How can different TWSIs be used together as a system for wayfinding across different transportation settings? While the UK has a broad array of TWSIs to draw upon, it is not clear that each pattern suggested in their 1998 guide is fundamentally discriminable from one another, as practice suggests that people who are blind may ‘recognize’ a specific TWSI pattern based more so from other context clues from the surrounding environment when they detect it than by identification based on feel of the tactile surface alone. Further research is needed to confirm that pedestrians with vision impairments can identify DWS and GS surfaces in the natural environment and correctly interpret and respond to them when they encounter them along a route that is comprised of a variety of environments and wayfinding challenges. It is not certain that an indicator surface is needed at intersection or turns in paths defined by GS, nor if a surface is needed, what that surface should be in order to be identifiable and correctly interpreted as indicating an intersection or turn. A trapezoidal surface recommended as a delineator between pedestrian and bicycle sides of a sidewalk level SBL, has repeatedly been found to be highly detectable, and also crossable by people having mobility disabilities, but there is a need to confirm that, the surface will work as intended in the natural environment and not be confused with any other TWSI. Beyond the three surface types needed to indicate warning, path, and (possibly) turn or choice point in the US, we may find that SBL delineators and a TWSI that aids in aligning to cross call for two more unique surface types for a possible total of five TWSIs. Other surfaces to more extensively consider for use in the US may include trapezoidal bar GS, corduroy GS, and a surface made from a rubber, resilient material. Alternately, research is needed to investigate whether one unique TWSI could convey more than one meaning based on the context in which it is installed. If that is the case, then the arrangement and location of the TWSIs may be more crucial to ensure the same TWSI pattern conveys the correct meaning for the correct situation. Moreover, research is needed to determine optimum geometries for use of TWSIs such that they can function as a system to promote locating street crossings, aligning to cross, guiding across open spaces such as plazas or transit facility lobbies, guiding to specific destinations such as transit fare machines, fare barriers, or boarding platforms, and wayfinding on shared streets. Ultimately research is needed to confirm that TWSIs that are highly detectable, identifiable, and discriminable function as a system to improve wayfinding performance, reduce confusion, and enhance confidence in travel on public rights-of-way and in transit facilities. It is anticipated that GS installed in different alignments or configurations can convey different meanings, such as indicating transit stops and indicating crossings, and be usable for establishing a heading to cross. This needs to be confirmed in the natural environment with real tasks of locating transit stops and locating crossings and aligning to cross. Consistency in where and how TWSIs are installed will be key to their effective use and correct interpretation by travelers with vision disabilities. Gap 6) What is the durability of different TWSI materials, how should they be maintained, and what operational impacts should be considered when installed in different contexts and in different weather environments? Much of the research found on maintenance needs for TWSIs has been done on DWS specifically. The information known about the performance and application of different materials for DWS should largely apply to other TWSIs used in similar applications. What remains a research gap is whether raised bars, trapezoids, corduroy, or rubber resilient surfaces have any unique maintenance needs or concerns requiring different operational techniques or knowledge to ensure their continued effectiveness. This may be particularly true in shared street environments where TWSIs may be driven over by motor vehicles, as noted

Final Report February 2024 Appendix A: Research Roadmap Page 92 by Elliot et al (Elliot et al. 2017). Anecdotal information from agencies interviewed also suggests that maintenance needs pertaining to rainwater management, drainage, and power washing or sweeping to clear debris out of TWSIs are considerations to ensure they remain detectable. Another maintenance concern could arise when using prefabricated TWSI tiles or panels arises when attempting to install them in a curvilinear path layout. Pedestrians tend to walk the shortest path from point A to point B, and that is no exception for those who are blind. This results in people naturally walking in curved arcs to avoid obstacles when navigating their route. Anecdotally, though, agencies tend to avoid installments of curving GS paths, opting for ‘zigzagging’ them instead through 90-degree or other obtuse angles to avoid making special cuts in surfaces into which tiles may be set or to avoid cutting the TWSI panels themselves. For example, the City of Charlotte found that cutting their DWS mats to fit the narrow angle needed to install them at bicycle ramps for roundabouts resulted in the DWS prematurely peeling back on that corner. Some manufacturers offer standard angle or wedge-shaped tiles, which may help. Methyl methacrylate (MMA) is another possible material for agencies where topography may lend to more horizontal and vertical curving, but no research was found to understand how pedestrians with vision impairments may follow along curved routes. In fact, only Seattle was found to be testing the use of MMA material so that they could lay out curved raised bar GS paths. Unfortunately, the consistency in applying the appropriate amount of material to maintain the required height profile of the TWSI is problematic. Coordinated or Parallel Research Projects Filling Gaps There are several research projects underway or completed with manuscripts under review that outside of TCRP B-46 which are investigating many of the research needs identified above. Members of our project team are involved in two of the more prominent projects which offers an opportunity for direct coordination across these projects. Other local agency evaluations were identified and are being monitored through relationships established with these agencies when conducting interviews to understand the state of the practice of guidance surfaces in the US. Finally, parallel research is underway to investigate other means of communicating wayfinding information to travelers via technological advancements. NIDILRR Administration for Community Living, Grant #90IF0127-01-00 “Effect of Guidance Surfaces on Travelers with Vision and Mobility Impairments” Addressing Research Gap 5 ADB and KAI are involved in this project which aims to provide research-based guidance for a TWSI to aid pedestrians with vision disabilities in locating crosswalks and aligning to cross, and to provide field- validated recommendations for optimal placement of the surface. The draft synthesis of literature on TWSIs compiled for the NIDILLR report was provided to the panel and served as the foundation for the development of B-46’s research roadmap. [Note: this report has since been published and is referenced in this appendix as Bentzen et al. 2021.] The first experiment of the project demonstrated that the orientation that provided the best alignment in earlier pilot research at non-corner crossings has minimal adverse effect on travelers with mobility impairments (Bentzen et al. 2017). At corner crossings where it is difficult to locate the crosswalk or to establish a correct heading, a 2-ft. square surface of raised bars oriented perpendicular to the direction of travel on the crosswalk promotes better alignment. Extending the raised bars across the sidewalk at corners seems to introduce more confusion than to help in locating crosswalks. At corners, the principal problem seems to be not locating crosswalks, but aligning to cross, especially where there are apex curb ramps, or parallel traffic is minimal (Bentzen, Barlow, and Scott 2019).

Final Report February 2024 Appendix A: Research Roadmap Page 93 San Francisco, Better Market Street project Addressing Research Gap 3 Some members of the TCRP B-46 project have also been concurrently investigating what pattern TWSI is effective to delineate sidewalk-level SBLs that also is not a barrier to people with mobility impairments. This study not only measured detectability of four different TWSIs but also considered the intrusion into the SBL of long white canes and people’s bodies across two different TWSI widths, which could cause harm to the bicyclist or pedestrian. The four TWSIs tested include: DWSs (having the narrow spacing that is preferred in San Francisco, and at 24 in. wide as the baseline), raised trapezoid, raised bar GS, and corduroy GS, with each of the latter two types being tested at both 24 in. and 12 in. widths. Participants with vision impairments were tested on two or three different tasks, depending on whether they used long canes or dog guides for travel: detecting the TWSI, identifying it underfoot, and following along the GS path (for cane users only). Participants with mobility impairments were asked to cross the test GS paths and rate their experience with respect to stability, comfort, and effort. A paper under review for TRB 2020 concludes that all four TWSIs were equally detectable regardless of width, and none appeared to be a barrier to those with mobility impairments, including the trapezoidal surface at 0.75 in. high and 6.33 in. wide at the top. Participants more accurately identified the raised trapezoid than the other three TWSIs, with the raised bars as the second-best performer for the identification task. Concerns still exist with the width of the trapezoidal GS, which was only tested on a 12 in base, given that TWSIs tested at 24 in. wide minimized long cane or body intrusions into the bicycle lane. Additionally, the lower performance of DWSs to be clearly identified as such (and not confused with raised bars or corduroy) calls for additional investigation of varying DWS dimensions within the 2010 ADA Standards to determine if the currently acceptable range should be more constrained to ensure DWS are not only detectable but discriminable from other TWSIs (Bentzen, Scott, and Myers 2020). Other local agency evaluations Addressing Research Gaps 3, 5, and 6 Additional ongoing assessments that may be fruitful to monitor are being conducted by local agencies in the US and Canada as they try new GS patterns to aid in wayfinding needs. While most of these studies appear to lack scientific rigor in their approach or are gathering more qualitative data on the agency’s experience with installation and operation and the public’s use of the TWSIs, the feedback may still be useful to follow: • The City of Vancouver, British Columbia, continues to test options for delineating pedestrian and cycle lanes that are usable by pedestrians with vision disabilities. The combined results of research on delineator strips for separated bike lanes at the same height, and their usability by cyclists, and travelers with either vision disabilities or mobility impairments, will inform the guidance for TCRP B-46. • New York City DOT has been investigating the use of TWSIs in their various plaza areas to assist blind pedestrians in navigating pedestrian and bicycle spaces and to define pedestrian spaces from shared street spaces. • BART’s Accessibility Improvement Program seeks input from a broad range of stakeholders through various public engagement processes and surveys on the different TWSI paths they have installed and future needs. • LA Metro will be evaluating TWSIs installed in five stations from late 2019 in to 2020 with plans to modify installations as needed in 2021.

Final Report February 2024 Appendix A: Research Roadmap Page 94 Parallel projects There are several other parallel projects to develop technology to enhance wayfinding for travelers with vision disabilities in transit environments. The user-interface for most of them is verbal directions for travel between nodes (such as from the fare barrier to the exit) that are provided by a hand-held device which may be a smart phone. Some of these technology projects are audio tactile maps developed by Touch Graphics, Click and Go Narrative Maps, Tiramisu Transit App, and PERCEPT. For example, Touch Graphics and the Rehabilitation Engineering Research Center of Smith-Kettlewell Eye Research Institute have developed a system of tactile crosswalk diagrams for aiding wayfinding at intersections for pedestrians who have vision disabilities. In addition, there are a number of products testing the combination of RFID or other type of beacons with information provided by the audio tactile maps. ACRP 07-13 “Enhancing Airport Wayfinding for Aging Travelers and Persons with Disabilities” developed a guidebook (publication pending) focused on “visual, verbal and virtual wayfinding aspects” to help airport operators and planners assist people navigating to waypoints within airports. Even with these explorations in technology, wayfinding information is largely not available or sufficient to enable people to regularly use fixed transit services particularly when their travel routes require moving through multimodal facilities. One project recently underway by the National Institute for Transportation and Communities (NITC) notes that few wayfinding options and technologies currently used are “not well- integrated and virtually none offer solutions for the seamless transition between indoor and outdoor spaces.” Their project will document and evaluate the validity and efficacy of wayfinding technology selection and develop an inventory of saliency features that support the wayfinding experiences of people with vision and hearing impairments (Swobodzinski and Parker 2019). While TCRP B-46 will aid in understanding and use of tactile pathways, these paths alone will not enable the advance planning still missing that could be served through additional research on how to best supply narrative routes and real-time location information through these types of technology solutions. Research Needs Addressed Through B-46 After assessing what is becoming known or should be resolved through other research underway, the following section identifies the remaining research gaps that will be the focus for B-46 work through Phases 2 and 3. Given that context based on land use, sound, and other cues may aid people who are blind in detecting TWSIs in a real-world environment, it is important that this research focus specifically on the fundamental performance of TWSIs tested to be detectable and identifiable purely through tactile cues based on surface geometries. Therefore, with the exception of testing a rubber surface as a choice point indicator, all other TWSIs tested will be made from the same material. Addressing Research Gap 1 Based on the preliminary findings from the Better Market Street study, the B-46 team will focus on testing how gap spacing to top-width dimensions impact detectability and identification task of two different DWS geometries and three different raised bar GS. This will be the focus of Experiment 1 in Phase 2. For all surfaces, raised elements will be 5 mm high. This decision was made to allow the detectability and discriminability tests to focus on the gap spacing to top-width ratios while controlling for height, given that previous research consistently validates that 5 mm is detectable while also being traversable by people with mobility impairments.

Final Report February 2024 Appendix A: Research Roadmap Page 95 Addressing Research Gap 2 Turns and intersecting paths may be denoted via a choice point indicator to test the impact and effectiveness of these treatments. This will be a focus of Experiment 2 in Phase 2. Addressing Research Gap 5 Finally, based on results found testing different TWSI geometries and components of a system via the Phase 2 lab experiments, the team plans to validate arrangements for how unique TWSI patterns can work together as a wayfinding system through various transportation settings in the real world as part of Phase 3. Remaining questions that will persist beyond the scope of B-46 or other ongoing research projects found include: • Research gap 4: nuances in height requirements for detectability and discriminability that may differ when TWSIs are used indoors and installed adjacent to smoother paving surfaces; and • Research gap 6: more thorough details, best practices, or life cycle cost considerations regarding maintenance and durability of different materials that may be suitable for TWSIs other than DWS which may be dependent upon on the location in which they are installed.

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